Lost Wi-Fi Connection - Assign Address Automatically

I went onto my home wi-fi network before work today and getting to my mail and internet was working fine. Got to work and went to my mail again and I get a message that the connection to server failed. So I went into my network setting and went to wi-fi and check the DHCP setting and so the ipad is giving it self a self assign address. So I go to another wi-fi in our building and try and connect. Again self assign address. I then go to a Airport base station in our office and it gets an address. Now for the strange part. My boss can take his ipad and get an address from both networks that I can't. Using the Airport base station I can get to the internet but I can't get my mail. I have Comcast and Yahoo and neither mail server will connect.